A multiburner furnace is a furnace having two or more burners. It is important that all burners be operating so that the furnace will achieve balanced heating in accord with its design. Furthermore, the supply of fuel and oxidant to an unlit burner could cause unsafe and inefficient operation of the furnace.
In a multiburner furnace having conventional burners wherein air is the oxidant, a problem with unlit burners generally does not arise. This is because such air burners are typically placed close together and should a burner fail to be ignited by its ignition system it will be ignited by the adjacent burner. In fact, often in such a system, one burner is ignited manually and this ignited burner will cause all the other burners in the multiburner furnace to become ignited.
A recent significant advance in the burner art is the burner described and claimed in U.S. Pat. No. 4,541,796 to Anderson which employs oxygen or oxygen-enriched air as the oxidant. This burner, as well as other oxygen burners, may be employed in multiburner furnaces, but, when so employed, the potential for certain problems, which does not arise with the use of air burners, come into being if less than all of the burners successfully ignite.
Because of the inherent higher efficiency of oxygen burners over that of air burners, fewer oxygen burners are needed for each furnace and thus oxygen burners are spaced farther apart than are air burners. This results in the inability of an unlit burner to be ignited by an adjacent firing burner due to the large distance between them. Furthermore, should one or more burners fail to ignite or become extinguished during operation, the entire furnace, including all of the ignited burners, must be shut down and the furnace zone repurged with air or an inert gas, because of the increased danger posed by uncombusted fuel mixing with the oxidant. This shutdown of the ignited burners and the repurging of the furnace zone is time consuming and costly.
It is therefore an object of this invention to provide a method for igniting all burners in a multiburner furnace without need to shut down ignited burners when less than all burners ignite initially.